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US 5,962,075 AGranted
Method of multilayer die coating using viscosity adjustment techniques
AssigneeAvery Dennison Corporation
InventorsLuigi Sartor, Stephen C. Huff, Craig N. Kishi, Daniel Meyer, Jesse C. Ercillo
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Abstract
A method for simultaneously coating multiple thin layers of relatively viscous fluids comprises the relative adjustment of the viscosity of the fluids in order to achieve a viscosity ratio in the optimum range without adversely affecting the adhesive properties of the fluids. In the preferrred method, viscosity is adjusted by varying the temperature of one or both fluids prior to coating and/or by reformulating the liquids to vary their relative viscosities.
Claims33
A method of coating two or more liquid layers onto a moving substrate, said substrate having a substantially planar surface to be coated and an opposite surface, said method comprising the steps of:
- providing a die for coating said liquid layers onto said substrate, said die having at least three lips formed thereon;
- said lips comprising, in the sense of direction of travel of said moving substrate, an upstream lip, a downstream lip, and a middle lip positioned between said upstream lip and said downstream lip;
- said die having an upstream feed gap separating said upstream lip and said middle lip and a downstream feed gap separating said middle lip and said downstream lip;
- providing a support along one section of said moving substrate and positioning said support so as to be adjacent said opposite surface of said substrate;
- positioning said die so as to be adjacent said moving substrate and opposite said support, said middle lip of said die being offset from said substrate to form a first coating gap, and said downstream lip of said die being offset from said substrate to form a second coating gap, each of said first and second coating gaps having a length as measured in the direction of travel of said moving substrate;
- feeding a first flow of liquid through said upstream feed gap and said first coating gap and onto said substrate to form a first wet layer coating on said substrate;
- feeding a second flow of liquid through said downstream feed gap and said second coating gap and onto said first flow of liquid to form a second wet layer coating on said substrate;
- the viscosity of said second flow of liquid within said second coating gap being about 50% less to 100% more than the viscosity of said first flow of liquid within said first coating gap;
- adjusting said first coating gap such that, along said length of said first coating gap, the minimum coating gap is not less than two times the thickness of said first wet layer, and the maximum coating gap is not more than three times the thickness of said first wet layer;
- and
- adjusting said second coating gap such that, along said length of said second coating gap, the minimum coating gap is not less than the total thickness of said first and said second wet layers, and the maximum coating gap is not more than two times said total thickness.
8 more elements
A method of coating two or more layers of liquids onto a moving substrate, comprising the steps of:
- providing a die for coating said liquids onto said substrate, said die having an upstream lip, a downstream lip, and one or more middle lips positioned between the upstream and the downstream lips, said downstream lip being located downstream from said upstream lip in the sense of substrate travel;
- each of said middle lips having a length along the direction of substrate travel and being set back from said substrate to form a coating gap therebetween for coating one of said layers onto said substrate or onto a layer coated through another coating gap formed between one of said middle lips and said substrate;
- adjusting viscosity of the liquid forming said one of said layers such that, within said coating gap, it is about 50% less to 100% more than viscosity of the liquid forming said layer coated through said another coating gap;
- adjusting coating gaps formed between each of said middle lips and the substrate such that, along the length of said each of said middle lips, each of said coating gaps is not less than two times and not more than three times total downstream wet film thickness of layers coated through said each of said coating gaps and those coating gaps upstream to said each of said coating gaps;
- and
- feeding said liquid forming said one of said layers through one of said coating gaps and onto said substrate or onto said layer coated through said another coating gap formed between said one of said middle lips and said substrate.
3 more elements
A method of manufacturing a multilayer product on a substrate by coating two or more layers of liquid onto said substrate, said coating process comprising the steps of:
- providing a die for coating said layers onto said substrate, said die having at least an upstream lip, a downstream lip being located downstream from said upstream lip in the sense of substrate travel and one or more middle lips positioned between said upstream lip and said downstream lip, each of said middle lips having a length along a direction of substrate movement;
- positioning each of said upstream, downstream, and middle lips on said die such that each of said lips is offset from said substrate to form a coating gap therebetween for coating one of said layers onto said substrate or onto layers previously coated thereon;
- adjusting coating gaps formed between each of said middle lips and the substrate such that along the length of said each of said middle lips, each of said coating gaps is not less than two times of and not more than three times total downstream wet film thickness of layers coated through said each of said coating gaps and those coating gap upstream to said each of said coating gaps;
- and
- feeding each of said layers of liquid separately through each of said coating gaps onto said substrate or onto said previously coated layers to form said product.
2 more elements
A method of adjusting the viscosity of two or more layers of liquid to be coated onto a substrate, said method comprising the steps of:
- providing a die for coating said layers onto said substrate, said die having at least an upstream lip, a downstream lip being located downstream from said upstream lip in the sense of substrate travel, and one or more middle lips positioned between said upstream lip and said downstream lip;
- positioning each of said middle lips on said die such that each of said middle lips is offset from said substrate to form a coating gap there between for coating one of said layers onto said substrate or onto layers previously coated thereon;
- determining the viscosity of a first liquid being passed through a first one of said coating gaps, said first liquid forming said one layer;
- determining the viscosity of a second liquid being passed through a second one of said coating gaps, said second liquid forming a contiguous one of said previously coated layers;
- determining the shear rates experienced by said first and second liquids in said first and second coating gaps;
- determining the viscosity of said first and second liquids at said shear rates;
- adjusting the viscosity of said first and second liquids so that in said first and second coating gaps the viscosity of said first liquid is about 30% more than the viscosity of said second liquid.
4 more elements
Dependencies are inferred from the claim text.